Work continues on electric properties of the surface membrane of Paramecium with special reference to the role of the calcium system in regulating direction and frequency of beating and the conductance of the membrane to other ions. Work has also begun on the role of Ca2 ion in regulating metabolism and pacemaker activity in molluscan neurons. BIBLIOGRAPHIC REFERENCES: Eckert, R. and H. D. Lux (1976) A voltage-sensitive persistent calcium conductance in neuronal somata of Helix. J. Physiol. 254: Eckert, R. and H. D. Lux (1976) Two actions of calcium on delayed outward current in small snail neurons. Fed. Proc. 35:846.